Patents by Inventor Sang R. Lee

Sang R. Lee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Private automatic branch exchange for integrated services digital network
    Patent number: 5579300
    Abstract: A private automatic branch exchange for an integrated services digital network, comprising primary rate interface boards. Each of the primary rate interface boards has a frame structure of 32 channels and layer-1, layer-2, layer-3 and operating system software to perform a subscriber's telephone function through interfacing with a data distribution board and a data switching board. Each of the primary rate interface boards provides a 2048 Kbps interface between the private automatic branch exchange and a central office exchange.
    Type: Grant
    Filed: May 2, 1995
    Date of Patent: November 26, 1996
    Assignee: Hyundai Electronics Industries Co., Ltd.
    Inventors: Sang R. Lee, Jin Y. Park